The present invention relates to the art of straightener machines and, more particularly, to improved arrangements for controlling the angular, or angular and vertical orientation of a straightener roll in such machines.
Straightener machines for working rod, tube or other elongate stock are of course well known. Such machines have a plurality of pairs of straightener rolls, each pair including an upper and a lower roll and which pairs are aligned along the machine axis or pass line with the horizontal roll axes of the upper rolls orientated at one angle and the axes of the lower rolls oriented at a different angle. The rolls are of concave contour and the latter together with the different angular orientation between the upper and lower rolls provides a path therebetween and along which stock to be worked is moved in response to driving of the upper and lower rolls.
It is likewise well known in such straightener machines to provide for the rolls to be individually adjustable angularly relative to a vertical roll support axis, and to provide for at least certain of the rolls to be vertically adjustable along the roll support axis. For example, in a six roll mill comprising three pairs of upper and lower rolls, the lower rolls of the outer pairs are angularly adjustable and vertically fixed, and the upper three rolls and the lower intermediate roll are each both angularly and vertically adJustable. It will be appreciated of course that both obtaining and maintaining optimum orientation of the straightener rolls is necessary to achieve desired diametral dimensions, straightness, roundness and other properties with respect to a workpiece being processed.
Heretofore, arrangements for achieving angular orientation of a straightener roll have included the use of a pair of manually rotated screws arranged to push against a support member for the roll on laterally opposite sides of the vertical axis. Other arrangements have included the use of a motor driven bellcrank mechanism and a pneumatically or hydraulically actuated device to lock the roll in an adjusted position. Such prior arrangements are disadvantageous for a number of reasons including the fact that the machine operator cannot conveniently or quickly make angular adjustments. In this respect, the operator must first release one or both of the manually rotated screws, or the pneumatically or hydraulically actuated lock mechanism, in order to free the roll for angular displacement. The operator must then make the desired adjustment through appropriate manipulation of the screws or the bellcrank mechanism and then relock the roll in the new position. Another disadvantage resides in the fact that the operator cannot conveniently or safely make angular roll adjustments while a workpiece is being processed. In this respect, it will be appreciated that releasing of the screws or the locking device during machine operation is hazardous and, more importantly, is undesirable if not intolorable from the standpoint of the effects thereof on the desired processing characteristics with respect to the workpiece. Any attempt to make an angular roll adjustment during machine operation requires considerable care and skill on the part of the operator, as does the initial set-up of angular orientation for the straightener rolls, whereby such set-up and adjustments of angular orientation are time consuming and tedious processes. This, together with the fact that the accuracy of initial set-up and subsequent angular adjustment of the rolls is dependent in a large part on the skill of the operator, can and does affect both the rate of production for a given machine and the quality of the work product.
Vertical roll orientation has been achieved heretofore generally through the use of manually or motor driven screw arrangements and locking devices for maintaining the roll in an adjusted position. Such adjusting screw arrangements do not enable an operator to conveniently or quickly make vertical adjustments during initial set-up, or to make vertical adjustments while a workpiece is being processed through the machine. In this respect, such vertical adjustment requires that the operator first release the angular adjusting screws or locking device, then release the vertical adjusting screw lock and make the vertical adjustment, then relock the vertical adjusting screw, and then reset the angular adjustment components. In addition to such a procedure being time consuming and tedious, it will be appreciated that release of the angular components promotes the probability of changing the previously established angular setting of the roll. Accordingly, the problems referred to hereinabove in connection with angular adjustment are compounded by the required vertical adjustment feature. An additional shortcoming of vertical adjusting screw arrangements is the existence of backlash in the mechanical components which adversely affects both obtaining and maintaining accuracy of a vertical setting.
It has also been proposed, as shown in U.S. Pat. No. 3,626,732 to Krafft et al and German patent application No. 2,349,693, to provide the lower roll of a machine for straightening workpieces of non-circular cross-section with a hydraulic biasing arrangement for vertically positioning a lower roll in a manner which enables the lower roll to vertically reciprocate during operation of the machine and in response to variations in workpiece contour which effect pressure conditions in the hydraulic system. Thus, the biasing arrangement is not capable of maintaining a relatively fixed vertical roll position as is required in connection with the straightening of circular workpieces, and for which use the lower roll in the machines in the Krafft et al and German patent application are adapted to rigidly engage against the machine frame. Moreover, both the upper and lower rolls in the latter patents are angularly adjustable through the use of screw arrangements and the upper roll is vertically adjustable through a screw arrangement whereby, in any event, vertical or angular adjustment of the upper roll and angular adjustment of the lower roll requires shut-down of the machine and presents the problems referred to hereinabove in connection with such screw type adjusting arrangements.